Add options(namespace) method to LocalDatastoreHelper

gcloud-java-datastore/src/main/java/com/google/cloud/datastore/DatastoreOptions.java

@@ -75,6 +75,9 @@ public DatastoreOptions build() {
       return new DatastoreOptions(this);
     }
 
+    /**
+     * Sets the default namespace to be used by the datastore service.
+     */
     public Builder namespace(String namespace) {
       this.namespace = validateNamespace(namespace);
       return this;
@@ -112,6 +115,9 @@ protected DatastoreRpcFactory defaultRpcFactory() {
     return DefaultDatastoreRpcFactory.INSTANCE;
   }
 
+  /**
+   * Returns the default namespace to be used by the datastore service.
+   */
   public String namespace() {
     return namespace;
   }

gcloud-java-datastore/src/main/java/com/google/cloud/datastore/testing/LocalDatastoreHelper.java

@@ -556,17 +556,28 @@ private static int findAvailablePort() {
     }
   }
 
+  private DatastoreOptions.Builder optionsBuilder() {
+    return DatastoreOptions.builder()
+        .projectId(projectId)
+        .host("localhost:" + Integer.toString(port))
+        .authCredentials(AuthCredentials.noAuth())
+        .retryParams(RetryParams.noRetries());
+  }
+
   /**
    * Returns a {@link DatastoreOptions} instance that sets the host to use the Datastore emulator on
    * localhost.
    */
   public DatastoreOptions options() {
-    return DatastoreOptions.builder()
-        .projectId(projectId)
-        .host("localhost:" + Integer.toString(port))
-        .authCredentials(AuthCredentials.noAuth())
-        .retryParams(RetryParams.noRetries())
-        .build();
+    return optionsBuilder().build();
+  }
+
+  /**
+   * Returns a {@link DatastoreOptions} instance that sets the host to use the Datastore emulator on
+   * localhost. The default namespace is set to {@code namespace}.
+   */
+  public DatastoreOptions options(String namespace) {
+    return optionsBuilder().namespace(namespace).build();
   }
 
   /**

gcloud-java-datastore/src/test/java/com/google/cloud/datastore/testing/LocalDatastoreHelperTest.java

@@ -16,6 +16,7 @@
 
 package com.google.cloud.datastore.testing;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
@@ -31,6 +32,7 @@ public class LocalDatastoreHelperTest {
 
   private static final double TOLERANCE = 0.00001;
   private static final String PROJECT_ID_PREFIX = "test-project-";
+  private static final String NAMESPACE = "namespace";
 
   @Test
   public void testCreate() {
@@ -49,5 +51,10 @@ public void testOptions() {
     assertTrue(options.projectId().startsWith(PROJECT_ID_PREFIX));
     assertTrue(options.host().startsWith("localhost:"));
     assertSame(AuthCredentials.noAuth(), options.authCredentials());
+    options = helper.options(NAMESPACE);
+    assertTrue(options.projectId().startsWith(PROJECT_ID_PREFIX));
+    assertTrue(options.host().startsWith("localhost:"));
+    assertSame(AuthCredentials.noAuth(), options.authCredentials());
+    assertEquals(NAMESPACE, options.namespace());
   }
 }